1. Field of the Invention
This invention relates to a projection type display apparatus, and more particularly to positional adjustment of parts of a projection type display apparatus.
2. Description of the Related Art
A projection type display apparatus which uses a reflection type light valve device is known as one of existing projection type display apparatus. One of such projection type display apparatus is disclosed, for example, in Japanese Patent Laid-Open No. 2005-250249.
FIG. 1 of the accompanying drawings shows an example of a general configuration of such an existing projection type display apparatus as mentioned above.
Referring to FIG. 1, the existing projection type display apparatus shown includes various components denoted by reference numerals 1 to 16 from a lamp house 1 to a projection lens 16. The projection type display apparatus emits a flux of light from the projection lens 16 to a screen 21 so that an image of the light flux is projected on the screen 21. In other words, a projected image is displayed on the screen 21.
The lamp house 1 includes a lamp bulb 1-1 serving as a light source, and a light condensing mirror 1-2 for condensing light emitted from the lamp bulb 1-1 and emitting the condensed light toward a desired direction.
The lamp bulb 1-1 is formed from a light source for radiating a flux of light over a wide frequency range such as a xenon short arc lamp or an ultra-high pressure lamp.
The flux of light emitted from the lamp house 1 is reflected by a mirror 2 and enters an optical system 3, by which it is shaped into a desired light flux. Then, the light flux passes through a first fly-eye device 4, a second fly-eye device 5, and a polarization control optical system 6 which shapes the light flux into a desired polarizing direction, and enters a color separation optical system 31 through an optical system 7.
A color separating system is provided in the color separation optical system 31 and includes dichroic mirrors 9 and 10 disposed in X-shaped arrangement. For example, in the example shown in FIG. 1, the dichroic mirror 9 reflects red wavelength light (hereinafter referred to as R light) while the dichroic mirror 10 reflects blue wavelength light (hereinafter referred to as B light) and green wavelength light (hereinafter referred to as G light). A pair of mirrors 8 and 11 is disposed so as to change the direction of the light flux passing through the color separating system. The color separation optical system 31 further includes a dichroic mirror 12 for reflecting the G light but transmitting the B light therethrough.
In particular, the R light reflected by the dichroic mirror 9 from within the light flux incoming to the color separation optical system 31 is introduced into a polarization beam splitter 13R after its direction is changed by the mirror 8. Meanwhile, the G light and the B light reflected by the dichroic mirror 10 are reflected by the mirror 11 to change their direction, and the G light is reflected by the dichroic mirror 12 and introduced into a polarization beam splitter 13G while the B light passes through the dichroic mirror 12 and is introduced into a polarization beam splitter 13B.
The R light incoming to the polarization beam splitter 13R is reflected by a polarizing film (hereinafter referred to suitably as polarizing separation portion) of the polarization beam splitter 13R and comes to a reflection type light valve device 14R. The reflection type light valve device 14R can control the state of the R light such that it arbitrarily adjusts the polarization state of the incoming R light for each very small region so that the R light passes through the polarizing separation portion of the polarization beam splitter 13R and introduced to a color synthesizing prism 15. In other words, the R light introduced from the polarization beam splitter 13R to the reflection type light valve device 14R is reflected by the reflection type light valve device 14R and introduced back into the polarization beam splitter 13R, whereafter it passes through the polarizing separation portion and then is introduced to the color synthesizing prism 15.
Similarly, the G light introduced from the polarization beam splitter 13G into a reflection type light valve device 14G is reflected by the reflection type light valve device 14G and then introduced back into the polarization beam splitter 13G, whereafter it passes through the polarizing separation portion and is introduced to the color synthesizing prism 15. Meanwhile, the B light introduced from the polarization beam splitter 13B into a reflection type light valve device 14B is reflected by the reflection type light valve device 14B and introduced back into the polarization beam splitter 13B, and then passes through the polarizing separation portion of the polarization beam splitter 13B and is introduced to the color synthesizing prism 15.
The color synthesizing prism 15 reflects the R light, G light and B light incoming from the reflection type light valve devices 14R, 14G and 14B so as to be directed toward the projection lens 16. The projection lens 16 emits a flux of light composed of the R light, G light and B light to project an image formed by the reflection type light valve devices 14R, 14G and 14B on the screen 21.
In short, to project an image on the screen 21 by means of the projection lens 16 signifies that the reflection type light valve devices 14R, 14G and 14B and the screen 21 are disposed at optically conjugate positions by the projection lens 16.
When such an image as described above is projected on the screen 21, a plurality of secondary light sources are formed in the proximity of the light emitting face of the second fly-eye device 5 from the first fly-eye device 4 and the second fly-eye device 5. The secondary light sources cooperate with the optical system 7 to form Koehler illumination and illuminate the reflection type light valve devices 14R, 14G and 14B.
In the existing projection type display apparatus having such a configuration as described above, in order to maximize the luminous intensity on the screen 21 on which an image is projected, positional adjustment of parts such as adjustment of the positional relationship between the light condensing mirror 1-2 and the lamp bulb 1-1, adjustment of the positional relationship between the lamp house 1 and the optical system 3 or adjustment of the inclination of the mirror 2 is performed as occasion demands. Upon such positional adjustment, a light reception sensor 22 for measuring the luminous intensity is disposed on the screen 21, and a display apparatus 23 for displaying a measurement value of the light reception sensor 22 is disposed in the proximity of the light reception sensor 22 as seen in FIG. 1.
In particular, an adjusting person would actually cause an image to be projected on the screen 21 from the existing projection type display apparatus and read the value of the luminous intensity measured thereupon by the light reception sensor 22 on the display apparatus 23 to perform positional adjustment of parts of the projection type display apparatus.